A widely used and successful commercial process for synthesizing acetic acid involves the catalyzed carbonylation of methanol with carbon monoxide. The catalysis contains rhodium and/or iridium and a halogen promoter, typically methyl iodide. The reaction is conducted by continuously bubbling carbon monoxide through a liquid reaction medium in which the catalyst is dissolved. The reaction medium also comprises methyl acetate, water, methyl iodide and the catalyst. Conventional commercial processes for carbonylation of methanol include those described in U.S. Pat. Nos. 3,769,329, 5,001,259, 5,026,908, and 5,144,068, the entire contents and disclosures of which are hereby incorporated by reference. Another conventional methanol carbonylation process includes the Cativa™ process, which is discussed in Jones, J. H. (2002), “The Cativa™ Process for the Manufacture of Acetic Acid,” Platinum Metals Review, 44 (3): 94-105, the entire content and disclosure of which is hereby incorporated by reference.
In the production of acetic acid there may be several limits on the capacity of the system. One such limit is the amount of reactants that may be fed to the reactor. Increasing the feed may require increasing the capacity of the pumps to handle the higher throughput. Reconfiguring the piping, foundations, and utilities, as well as the associated reconfiguration downtime, makes changing over to larger-capacity pumps economically unattractive. Also these pumps are typically high pressure pumps which are more expensive.
There remains a need to continue to improve the capacity for producing acetic acid. The present invention provides such a need.